It is well known that color photographs are formed by methods comprising processing photographic materials having dye forming couplers and silver halide emulsions on supports with aromatic primary amine color developing agents, and reacting oxidation products of the developing agents formed thereby with the dye forming couplers (hereinafter referred to as couplers) to obtain dye images.
Easy rapid processing in this color development has been very strongly required in the color photographic industry. According to this requirement, great many improvements have been achieved, and new, more easy rapid systems has been developed for every several years.
It is necessary for rapid processing that a reduction in time is separately devised for each stage of color development, bleaching-fixing, washing and drying. As a method for rapid processing, PCT International Publication No. W087-04534 discloses a method in which a high silver chloride color photographic material is rapidly processed with a color developing solution substantially free from sulfite ions and benzyl alcohol.
High silver chloride silverhalide emulsions to be used in this method are known to be generally low in sensitivity. For practical use, this has been a problem to be overcome.
High silver chloride emulsion grains are usually liable to become cubic crystalline grains having (100) outer planes. However, it is possible to form grains having (111) outer planes by existence of a grain forming controlling agent. A method for obtaining tabular high silver chloride grains having the (111) planes as main planes by forming grains in the presence of a compound containing a sulfur atom in a heterocycle is described in JP-A-63-2043 (the term "JP-A" as used herein means an "unexamined published Japanese patent application"). Tabular grains are known to be highly sensitizable by the use of a large amount of a sensitizing dye because of their large surface area.
However, the tabular high silver chloride emulsion grains having the (111) outer planes are weak in absorption of the sensitizing dye, compared with the high silver chloride emulsion grains having the (100) outer planes, which causes the problem that photographic characteristics considerably changes with time after preparation of a coating solution.
The tabular high silver chloride emulsion grains having the (100) planes as main planes have been desired to be further improved in terms of variations in sensitivity between production lots of photographic materials, or due to a storage period or storage conditions after production.
JP-A-4-323645 proposes a method for suppressing a decrease in photographic sensitivity in the infrared light region of emulsions stored in the solution state before coating and photographic materials during storage after coating by adding a thiocyanate or a selenacyanate to the high silver chloride emulsion containing the tabular high silver chloride emulsion grains having the (111) planes. However, this method is not sufficient for practical use.